1) Field of the Invention
The present invention is related to the field of cargo handling, and more particularly, to a system, apparatus, and method for efficiently loading cargo from a loading dock and into a transport vehicle and vice versa.
2) Description of Related Art.
Various techniques are utilized for loading and unloading large cargo loads from aircraft, ships, trucks, and similar transport vehicles. Typically, the cargo consists of large containers that are arranged in series and may be loaded concurrently from a loading dock onto the transport vehicle and vice versa. One technique to transport several containers between the loading dock and the transport vehicle is a trolley that may travel on rails. Thus, the containers are loaded pallets on the loading dock, the trolley transports several containers onto the transport vehicle at one time, and the trolley is removed from the transport vehicle. Similarly, to remove the containers from a transport vehicle, the trolley travels into the transport vehicle and transfers the containers to the loading dock, where the containers may then be positioned for further handling.
An example of a system for transporting cargo is disclosed in U.S. Pat. No. 6,435,796 to Iversen. Iverson discloses trolley trains that may travel on rails located on both the deck of a vessel to be loaded and corresponding rails on a loading dock. The trolley trains include cargo trolleys having lifting and driving equipment for lifting cargo pallets, as well as a power trolley for propelling the trolley trains. Each of the cargo trolleys and power trolley are configured to be positioned under load bearing or cargo platforms. The cargo trolleys include guide pins at the top of each trolley that mates with holes in the bottom of the individual platforms. Each of the cargo trolleys lifts each platform from the loading dock and travels along rails onto the vessel and is subsequently lowered such that securing elements are lowered into positioning stands. Similarly, conical studs may be employed on the loading dock and/or on the cargo deck of the vessel that mate to corresponding holes in the platform legs when the platform is lowered to ensure correct platform positioning. Once the platform is lowered onto the vessel, each of the trolleys may then be removed from the vessel, while the train of platforms and associated cargo remains on the vessel. Iversen further provides trolley locking arms that are brought into contact with protruding platform locking arms such that as the trolley is removed from the transport vessel, the platform locking arms are pivoted to a locking position. When the trolleys are transferred back to the transport vessel, each of the platform locking arms are unlocked from the locking position so that the platforms and cargo may be removed from the transport vessel.
Thus, the Iversen patent provides trolleys for transporting a train or trains of platforms supporting cargo between a loading dock and a transport vehicle. Despite these improvements, techniques for more efficiently and effectively transporting cargo are required. For instance, a cargo handling system that is capable of handling standard ISO containers is desired. ISO containers are designed to be handled and carried almost exclusively by standard fittings located at the each corner of the rectangular container. In contrast to platforms and pallets designed for standard cargo systems, the bottom surface of the ISO container is not smooth and is not load-bearing. For instance, conventional aircraft cargo handling systems that employ a series of floor-mounted rollers to allow pallets to be moved within the airplane is not suitable for ISO containers.
Conventional cargo pallets and containers, such as those disclosed in Iversen, are restrained within the transport vehicle by a system of rails and locks that engage detents in the pallet or platform. These conventional systems (and variations on them) will not work with the geometry of the ISO container. Systems used in ships, trucks, and trains for restraining ISO containers are designed to engage the ISO container as it is lowered vertically from above. With respect to aircraft, this technique is unsuitable for aircraft that have no opening above the cargo deck such that loading from above and using existing restraint systems is not possible.
Furthermore, conventional cargo handling systems that utilize pallets and platforms impose a large weight penalty for transport vehicles. The weight penalty must take into consideration the weight of the cargo handling system as well as the additional weight of the vehicle structure to support the cargo. Thus, a smaller weight penalty is desired, such as for container-carrying aircraft, where excess weight has a negative impact on fuel efficiency and aircraft operating cost.
It would therefore be advantageous to provide an improved cargo handling system that is capable of transporting cargo into and within a transport vehicle. In addition, it would be advantageous to provide a cargo handling system that is effectively restrained within the transport vehicle. It would also be desirable to provide a cargo handling system that requires a reduced amount of time and workforce to load and/or unload the cargo into and/or out of the transport vehicle. It would be further desirable to provide a cargo handling system that does not increase the weight penalty on the transport vehicle, as well as a compact cargo handling system that reduces the size, weight, and surface area required to accommodate the cargo within the transport vehicle.